A display device which utilizes the electro-optical effects of a liquid crystal and the light emission phenomenon of an organic electroluminescence material is arranged with a terminal part at one end of a substrate which is input with a control signal (video signal, clock signal etc.) for display an image. For example, a display device arranged with a pixel circuit using a thin film transistor arranged above a glass substrate is arranged with a terminal part input with a video signal at an end part of the glass substrate. The terminal part is connected with a flexible wiring substrate (also called a FPC “flexible printed circuit” substrate herein) using an anisotropic conductive film.
Each terminal electrode in a terminal part requires the formation of a good contact (electrical connection) with a FPC substrate. For example, a structure is disclosed in Japanese Laid Open Patent Publication No. 2003-202583 in which irregularities are provided to the surface of a terminal electrode so that conductive particles included in an ACF are securely captured between the terminal electrode and an electrode of a FPC substrate.
An ACF combines fine conductive particles in a thermosetting resin. A terminal part and FPC of a display device are electrically and physically connected by thermo-compression sandwiching an ACF. When adhesion of the ACF is weak at this time, the FPC substrate peels away from the display device. That is, even when conductive particles are captured above a terminal electrode, when adhesion with a thermosetting resin is weak, the reliability of an electrical connection decreases.